1-1-2 Discoveries in Functional Localization
The question of how to distinguish between motor information (information leaving the brain) and sensory information (information travelling to the brain) was answered by a Scottish surgeon; Charles Bell ( 1774-1842 ) and a French physiologist; Francois Magendie (1783－1855 ) through anatomy.
They observed that the sciatic nerve was composed of two fascicles of the nerve fibers;the so-called "ventral root" from the ventral side of the spinal cord and the "dorsal root" from the dorsal side.
Furthermore, they clarified that the ventral root caused movement and the dorsal root transmitted sensory signals from the periphery. (Fig.2)
Challenge Quiz
Charles Bell and Francois Magendie clarified that the output signal from the brain (1)（ motor signals sensory signals pain signals ）and the input signal into the brain (2)( motor signals sensory signals pain signals ) take different channels.
The sciatic nerve contains the two nerve fascicles; one involved with the output signal and the other involved with the input signal. The output signal arises from the (3)( dorsal ventral rostral caudal ) side of the spinal cord and the input from the (4) ( dorsal ventral rostral caudal ) side, which are called the (5)( dorsal root ventral root rostral root caudal root ) and (6) ( dorsal root ventral root rostral root caudal root ).